Avalonia/samples/interop/NativeEmbedSample/WinApi.cs

using System;
using System.Runtime.InteropServices;

namespace NativeEmbedSample
{
    public unsafe class WinApi
    {
        public enum CommonControls : uint
        {
            ICC_LISTVIEW_CLASSES   = 0x00000001, // listview, header
            ICC_TREEVIEW_CLASSES   = 0x00000002, // treeview, tooltips
            ICC_BAR_CLASSES    = 0x00000004, // toolbar, statusbar, trackbar, tooltips
            ICC_TAB_CLASSES    = 0x00000008, // tab, tooltips
            ICC_UPDOWN_CLASS       = 0x00000010, // updown
            ICC_PROGRESS_CLASS     = 0x00000020, // progress
            ICC_HOTKEY_CLASS       = 0x00000040, // hotkey
            ICC_ANIMATE_CLASS      = 0x00000080, // animate
            ICC_WIN95_CLASSES      = 0x000000FF,
            ICC_DATE_CLASSES       = 0x00000100, // month picker, date picker, time picker, updown
            ICC_USEREX_CLASSES     = 0x00000200, // comboex
            ICC_COOL_CLASSES       = 0x00000400, // rebar (coolbar) control
            ICC_INTERNET_CLASSES   = 0x00000800,
            ICC_PAGESCROLLER_CLASS = 0x00001000,  // page scroller
            ICC_NATIVEFNTCTL_CLASS = 0x00002000,  // native font control
            ICC_STANDARD_CLASSES   = 0x00004000,
            ICC_LINK_CLASS     = 0x00008000
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct INITCOMMONCONTROLSEX
        {
            public int dwSize;
            public uint dwICC;
        }

        [DllImport("Comctl32.dll")]
        public static extern void InitCommonControlsEx(ref INITCOMMONCONTROLSEX init);

        [DllImport("user32.dll", SetLastError = true)]
        public static extern bool DestroyWindow(IntPtr hwnd);

        [DllImport("kernel32.dll")]
        public static extern IntPtr LoadLibrary(string lib);


        [DllImport("kernel32.dll")]
        public static extern IntPtr GetModuleHandle(string lpModuleName);

        [DllImport("user32.dll", SetLastError = true)]
        public static extern IntPtr CreateWindowEx(
            int dwExStyle,
            string lpClassName,
            string lpWindowName,
            uint dwStyle,
            int x,
            int y,
            int nWidth,
            int nHeight,
            IntPtr hWndParent,
            IntPtr hMenu,
            IntPtr hInstance,
            IntPtr lpParam);

        [StructLayout(LayoutKind.Sequential)]
        public struct SETTEXTEX
        {
            public uint Flags;
            public uint Codepage;
        }

        [DllImport("user32.dll", CharSet = CharSet.Unicode, EntryPoint = "SendMessageW")]
        public static extern IntPtr SendMessage(IntPtr hWnd, int Msg, ref SETTEXTEX wParam, byte[] lParam);
    }
}